ok here goes,
I used to work for samsung for sales training and marketing and this is what I remember.
LED's use less power then plasmas
Lighter
No screenburn issues like plasmas
Better picture colours
Smoother motions (100hz as opposed to plasma 600hz sub motion)
Samsung used to make 42" screens but faced many problems as did Sony. It was something to do with the placement of each pixel on the panel so they scrapped the idea and just stuck to 40" screens
Ive had 2 samsungs
UE40C6000 and the UE40D6530. These were the 2 best selling models in the previous 2 years.
Im looking to get another one for my living room. UE40ES5520. at john lewis its 449.00 with 5 year guarantee.
Also dont be confused by the CMR number Samsung advertise. Just remember if youre looking for a tv with 100hz in the samsungs, its going to be a 6,7 or 8 series.
I have 3D but never use it.
Also found that samsung tvs play all major formats. I remember a customer once returned a panasonic as it didnt plat mp4's and buy a samsung.
also dont go for a EH model ( EH5000, EH5300) these have a larger rear end like an LCD except it has an LED backlit. it kinda defeats the point of having an LED tv. apprently the speaker is better in them.
Stick to the ES models.
PS: hope i havent offended any plasma fans. Just my 2 pence.